The Journal of Vascular Access

Vascular access efficiency is a major determinant of an adequate dialytic treatment and reports from literature indicates a growing interest in the field of central venous catheterisation as permanent vascular access for hemodialysis. The main reasons are the continuous improvement in design and biomaterials along with the increased number of patients with failure of their vascular beds. In this paper it is presented and commented a series of negative crucial factors which can reduce the quality of the hemodialysis treatment: the problem of recirculation and the catheter related (and the patient related) causes of inadequate flowrate. Finally the Authors conclude with a short presentation of their clinical experience in the field.

The temporary vascular access is the essential condition required to perfrom hemodialysis in uremic patients in the absence of a permanent and utilizable vascular access. The cannulation of a central vein with a dual lumen catheter may be useful when a few weeks are required for the maturation of AVF. Longer times for AVF maturation (such as in diabetic patients and in aged patients) impose the use of a tunnelled catheter such as Tesio Catheter or Hickman Catheter which lead to minor complications and more efficient dialysis treatment. The Ash Split Cath^®, a recently introduced chronic hemodialysis catheter, provides dialysis via a transcutaneous portion containing a 14 French cylindrical shaped catheter with D-shaped lumens and a dacron cuff.

Due to the slow maturing of AVF, in our Department the Ash Split Cath has been used in 7 uremic patients (3 males and 4 females) who required hemodialysis.

The cannulation of the internal jugular vein was performed by an ultrasound assisted technique and the correct catheter position was verified by standard chest X-rays.

The average blood flowrates were 250 ml/min, and the mean KT/V calculated in all patients one month after the beginning of the dialytic therapy was 1.09 ± 0.02. In six patients the catheter was utilized for at least 4 months, in one patient for 8 months. The devices were easily removed when the patient's AVF was functional and usable.

We found that the use of the Ash Split Cath as a temporary, prolonged vascular access in uremic patients was optimal allowing for flexibility in organizing the dialysis treatment schedule and in yielding a good performance in the initial dialysis therapy. Moreover, this device allows, in these patients, a satisfactory dialysis efficiency.

This study observes the development of brachial arteriovenous fistulae, and assesses methods of predicting potential usefulness for haemodialysis. Creation of an adequate brachial fistula causes significant changes in blood flow to the forearm and hand.

A prospective study of fifteen consecutive patients undergoing brachial arteriovenous fistula formation for haemodialysis was undertaken. Clinical measurements and coloured flow Doppler measurements were performed pre operatively, immediately post operatively and at two and eight weeks after surgery. The morphology of the fistula was studied and the volume flow was measured. Digital pressure was measured pre and post exercise at each visit.

Fourteen fistulae worked well by eight weeks. There was an immediate large increase in brachial artery blood flow and by two weeks all fistulae that went on to develop well had a brachial artery flow of more than 700 mls/minute. The cephalic vein mean diameter pre operatively was 2.39 mm and increased to 5.4 mm by two weeks post operatively. Fistulae with flows over 400 mls/minute at two weeks had a good outcome. There were significant differences in digital pressure after fistula formation (P ≤ 0.05). Digital mean arterial pressure dropped from 118 mm Hg pre-operatively to 98 mm Hg post operatively, at rest, and 89 mm Hg after exercise. Four patients developed forearm/hand claudication on exercise or signs of distal ischaemia. Three of these were diabetic with calcified vessels.

All patients with a suitable cephalic vein should have attempted fistula formation rather than recourse to use of a synthetic graft. In diabetics creating a shunt in an already marginally competent vascular tree exposes the patient to risk of significant hand ischaemia.

Vascular access may be of crucial importance in long-term dialyzed patients when traditional blood access fails.

Long-term central vascular access devices are usually inserted in the internal jugular or subclavian veins but thrombosis may be the major factor limiting their long-term use. To solve this problem the Tesio caheter is one of the most commonly recommended tools for long-term use in RD patients, and is normally placed in the neck veins.

In this study the femoral vein is indicated as an alternative site for positioning the Tesio catheter. The “high” exit (abdominal) reported here presents some advantages for the patient who can then walk without difficulties while maintaining a high blood flow that is similar to those achieved with catheters implanted in other sites.

The jugular vein catheterism (JVC) is adopted for blood access in patients with acute renal failure, in chronic renal failure and when patients show failure of traditional vascular access. The technique of catheter insertion in the jugular vein is quick and easy. Usually correct catheter positioning, before starting the dialytic procedure, is controlled by chest X-ray or by intra-cavitary electrocardiogram. The aim of this work is to evaluate the feasibility of the real-time ultrasound guidance to control the correct positioning of the catheter instead of the usual chest X-ray control. We have studied 158 patients with JVC insertion before the hemodialytic procedure; 54 patients have undergone both ultrasound and a chest X-ray control while 104 were only submitted to ultrasound control. The ultrasound procedure includes an under xifoid scanning, with a convex 3.5 Mhz drill to evaluate the four heart cavities. When the right atrium is identified a second operator rapidly infuses in the venous catheter 15 ml of physiological solution thus creating a blood turbolence easily observed in real time as a light jet inside the atrium. This turbolence appears to be the main evidence for good catheter positioning and we were able to show the light jet in 156 (98%) patients. All light jet positive patients were submitted to the hemodialytic procedure without any complications during and after dialysis. We concluded that the intraoperative ultrasound control technique is an alternative to the chest X-ray evaluation because it offers the possibility for safe intraoperative immediate control thus reducing the total costs of the procedure.

One of the last options, when the other possibilities of vascular access present malfunction, is the insertion of a permanent catheter in a central vein, preferentially internal jugular vein. This option is considered when arteriovenous access is impossible. We report a case of malfunction due to a permanent catheter displacement solved by vascular interventional radiology.